The results suggested that there is little difference between the two types of lasers-Er:YAG and Er,Cr:YSGG lasers-morphologically for class V cavity preparation, because both lasers were capable of preparing class V cavities, and the morphological features of the irradiated surfaces were very similar.

Cervical dentine hypersensitivity is the most frequent complaint among reported odontalgias. Thus, this study evaluated the effectiveness of two types of lasers (660 nm wavelength red, and 830 nm wavelength infrared) as dentine desensitizers, as well as both the immediate and late therapeutic effects in individuals 25 to 45 years of age. A total of 40 teeth with cervical exposure were treated in 4 sessions. They were divided into 2 groups according to treatment. A 660 nm wavelength red diode laser and an 830 nm wavelength infrared diode laser were used. Dentine sensitivity to cold nociceptive stimulus was evaluated by means of a pain numeric scale from zero to 10 before each treatment session, at 15 and 30 min after irradiation, and in a follow-up period of 15, 30 and 60 days after the end of treatment. Significant levels of dentinal desensitization were only found in patients ranging in age from 25 to 35 years. The 660 nm red diode laser was more effective than the 830 nm infrared laser and a higher level of desensitization was observed at the 15 and 30 minute post-irradiation examinations. The immediate and late therapeutic effects of the 660 nm red diode laser were more evident in 25-35-year-old patients compared with those of the 830 nm infrared diode laser, in terms of the different age groups.

The aim of this study was to assess the effect of 635- and 670-nm laser irradiation on H.Ep.2 cells in vitro using MTT. In addition to our previous report on the effects of LLLT on the proliferation of laryngeal carcinoma cells in which it was found that irradiaton H.Ep.2 cells with 670-nm laser results in increased cell proliferation, it was decided to evaluate the effect of increased doses of laser light on these cells. The cells, obtained from SCC of the larynx, were routinely processed from defrost to the experimental condition. The cultures were kept either at 5% or 10% of FBS. Twenty-four hours after transplantation, the cells were irradiated with laser light (5-mW diode lasers; 635 and 670-nm; beam cross section approximately 1 mm) at local light doses between 0.04 and 4.8.10(4) Jm(-2). For 670 nm, significant differences in the proliferation were observed between the two concentrations of FBS (p = 0.002) and between irradiated cultures and controls (p = 0.000). Although the results were not significant, 635-nm irradiated cells also proliferated more than nonirradiated ones. This occurred under both conditions of nutrition. It is concluded, that irradiation with 670-nm laser light applied at doses between 0.04 and 4.810(4) Jm(-2) could significantly increase proliferation of laryngeal cancer cells.

Laser therapy was effective in preventing and treating oral effects induced by radiotherapy and chemotherapy, thus improving the patient's quality of life.

Er:YAG laser irradiation with 180 mJ could produce chemical changes in proteins, phosphate, and carbonate in dentin.